City landlord Mahadaye "Mala" Khan warned a fellow Trinidadian immigrant she "knows people" — and told him he could be murdered if he stopped working for her as a jack-of-all-trades, the man testified Tuesday.

Suresh Gunness, 35, told jurors at Mala Khan's labor trafficking trial in Albany County Court that the landlord made the not-so-subtle threat to him in 2009 after he begged her to let him visit his mother, who had just suffered a heart attack in his native Trinidad and Tobago.

Khan told him his "job comes first" and he should not go, then allowed him to visit his mother for three to four days, Gunness said, crying.

"She also indicated that if I don't come back she would have me killed," Gunness testified. "She said her brother got away with murder and she could get away with it, too. So I made sure to come back within the four days."

Khan, 52, and her daughter, Shereen Khan, 28, are on trial on allegations that they stole security deposits from tenants intended for the Albany County Department of Social Services. Prosecutors allege Mala Khan forced Gunness to work for her under threat of deportation while withholding his passport, green card and plane ticket.

Gunness said he did not return the documents to Mala Khan after he visited his mother because he planned to return to his homeland in 2010 for his sister's wedding, a visit he made. Defense attorneys have said those trips show Gunness was hardly being forced to work for Mala Khan since he could leave the country — and they note Mala Khan supplied Gunness with airfare and spending money.

The alleged death threat to Gunness only became known to prosecutors last weekend, Assistant District Attorney Jessica-Blain Lewis told the judge. She said Mala Khan also told Gunness: "I know people."

Mala Khan's attorney, Gaspar Castillo, asked acting Supreme Court Justice Roger McDonough to block the alleged threat from the trial because it was prejudicial. The judge denied the request.

Gunness, known as "Donnie," testified that he came to the United States on July 5, 2003, with just $400 for a six-month "vacation." He stayed with a friend's relatives in Queens but left three weeks later because they had a family emergency. He said he planned to return home, but his sister hooked him up with Mala Khan through in-laws.

Gunness said Mala Khan duped him into a sham marriage to stay in the U.S., provided him with a phony identification and had him attest to false information about his wife, Lisa Zeccola. He said Mala Khan convinced him to get his sister, Shivannie, to work for her; the sister, Gunness said, went back home after being treated badly by Mala Khan.

Gunness testified his "day and night" work for Mala Khan ranged from child care to pest control to roof replacement and extensive renovation work on properties that Khan's family owns in Albany, Colonie, Rensselaer and Niskayuna.

Gunness testified he belongs to a lower caste than Khan in their homeland, an allegation disputed by Castillo. The lawyer suggested to Gunness the caste system in Trinidad and Tobago ended more than 100 years ago. Gunness said the caste system remains today.

In often combative cross-examination, Castillo questioned how Gunness could be in a lower caste than Khan yet eat at her dinner table and use her pool.

Bryan Rounds, the attorney for Shereen Khan, later asked Gunness about several photos — one of which appeared to show Mala Khan's head resting on Gunness' shoulder.

"Did anyone say, 'Get your lower-caste butt out of the pool — we don't want to mix water with you?'" Rounds asked.